HR: 1340h
AN: SA23A-1127    [Abstracts]
TI: Contribution of the N2(A)+O Reaction to Thermospheric Nitric Oxide
AU: * Yonker, J D
EM: yonker@vt.edu
AF: Virginia Tech, Dept. of Physics, Blacksburg, VA 24060,
AU: Stern, T
EM: fstes@uaf.edu
AF: University of Alaska, Fairbanks, Geophysical Institute, Fairbanks, AK 99709,
AU: Bailey, S M
EM: scott.m.bailey@vt.edu
AF: Virginia Tech, Dept. of Physics, Blacksburg, VA 24060,
AB: A time-dependent photochemical model of thermospheric nitric oxide (NO) including the N₂(A³Σ_u⁺,v) + O(³P)→NO(X²Π) + N(²D) reaction (\ital{Thomas and Kaufman,J.Phys.Chem.,1996)} is compared with Student Nitric Oxide Explorer (SNOE) data over an altitude range of 90-170 km for a period of ± 45 days surrounding the 1999 vernal equinox. While including this reaction affects the modeled NO production rate primarily at altitudes > 130 km, as a result of diffusive coupling the modeled NO density is also enhanced at lower altitudes. The altitudes may be classified into three zones depending on the type of diffusion predominating within each: 90-100 km, 110-170km, and 100-110 km where the vertical transport is respectively controlled by eddy diffusion, molecular diffusion, and a mixture of the two. Correspondingly, it is found that inclusion of the title reaction in the existing model increases the equatorial NO density at 11 AM LST by an average of 13%, 44% and 28% in these regions. Comparison with the zonally-averaged SNOE data reveals that over the full range of altitudes the averaged daily error between model and data is 18% upon inclusion of the title reaction. More specifically, in the 90-100 km, 100-110 km and 110-170 km regions it is 23%, 29% and 15%, respectively. In addition, the differences between model and data comparisons are evaluated using more recently published reaction and diffusion rate coefficients, but it is found that the overall agreement between model and data is best when the only adjustment to the model is the title reaction itself.
DE: 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE
DE: 0317 Chemical kinetic and photochemical properties
DE: 0322 Constituent sources and sinks
DE: 0355 Thermosphere: composition and chemistry
DE: 0358 Thermosphere: energy deposition (3369)
SC: SPA-Aeronomy [SA]
MN: 2007 Fall Meeting